Aphis fabae


  1. Top Tips & Info
  2. Symptoms
  3. Susceptible Plants & Parts
  4. Actions Needed (Includes pros & cons of Chemical or Organic based pesticides)
  5. Ways to Prevent an Attack in the Future

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Top Tips & Info

  • Eradication Difficulty - Easy
  • Life Cycle - Up to twenty-five days.
  • The female can lay up to twenty eggs a day - five hundred in total.
  • Blackfly will attack all plant parts above the soil, most notably being the new growth and flowers.
  • Remove and crush all of the visible bugs using your fingers or a damp cloth.
  • Prune off the severely affected growths and any flowers that house the infestation.
  • Take the plant outside and perform a gentle hose-down. Aim at the cubbyholes for complete obliteration and replace the top inch of the soil to remove any live bugs that have fallen.
  • Allow the plant to dry off before applying either an organic or chemical-based pesticide.
  • Repeat the wiping, hosing-down and pesticide steps every 7 - 14 days, for the next month. Quarantine the affected plants to avoid spreading the infestation for at least a month, although Blackfly tend to infest one plant at a time.


Blackfly can attack all plant sections above the soil line. Not only will you notice the live bugs, but after a while, you'll also see white exoskeletons that look a little like Whitefly - these are the casings that are left behind between transitions. Fortunately, they won't do too much damage quickly, meaning that you'll still have time to save it from dying. Immediately keep the affected plant away from others to prevent a further infestation.

Susceptible Plants & Parts

The main sites of infestation are on the tissues that are weak and easy to penetrate, which includes the juvenile growth, flowers and the flower shafts. Blackfly can, however, attack all non-wooded structures of a plant.

Plants - Most species are susceptible to this pest, including Roses, Streptocarpus & Umbrella Trees.

Actions Needed

1. Prune away the new growths or flower stalks even if no pests are visible. If you can't remove the new growth or flowers, rub your fingers across the affected areas to destroy their mouthparts, although this won't entirely eradicate the population. 

2. Decide whether to use an organic or chemical-based pesticide. Of course, using the organic route is both natural and beneficial for the plant, but will generally work slower than the latter. Keep reading to find out about the different options to consider.

3. Keep the affected plant away from others in a quarantined room until the symptoms have subsided for at least four weeks. Always be wary of a relapse, and keep an eye out for possible outbreaks for several months after the last sighting.

N. B. - Although you should perform the wiping and hosing-down process BEFORE each pesticide application, you can wash the foliage at any given time to keep the infestation under control.

Blackfly are part of the Aphid family. 

Organic Pesticides

Predatory Mites - Releasing Predatory Mites on your affected houseplant's foliage is a more natural approach to controlling the infestation. We recommend doing your own research on which Mites work for you, as there are many around to purchase.

Garlic Water - The scent of garlic will quickly deter the inhabitants from your plant. To create the homemade spray, place a garlic clove in boiled water and allow to sit for around twenty minutes. Spray the entire foliage once the temperature cools down, empathising the infestations and specific bugs. Unfortunately, the remedy must come wholly in contact with the pests to entirely kill them, meaning that precision is critical. You'll immediately notice a significant decrease in the overall population of the infestation, but repetition is vital. Spray the foliage weekly for around a month with a gentle hose; always quarantine the plant until there are no signs of an attack for a month. Allowing a cooling-off' period after the last visible attack will ensure that the infestation won't return later down the line. Leftover garlic should be used within one week of mixture, or it'll go off. The remedy can be applied both either cool or warm, with no difference between the two.

Neem Oil - This is by far the most effective and popular around the world. Not only will many online stores sell it, but it'll get to work after the first application. Dilute the liquid, (to the manufacturer's recommended strength) with water and/or dish soap and spray thoroughly onto the foliage and its cubbyholes. Any flowers must be removed instead of misted, due to the heightened chance of another infestation.

Diatomaceous Earth (D.E. or DE) is grounded diatom mantels (skeletons) that can be highly abrasive to many arthropods, including Blackfly. Although the white powder may be soft to the human touch, the sharp tooth-like edges off each grain will begin to cut its way into the pests' eco-skeleton, causing significant discomfort and weakened health. After a period of several days, the infestation will decrease as the mature mothers won't be able sufficiently to lay her eggs. Usually, DE is applied as a thin layer across the foliage of outdoor plants, which will work until there is a rainstorm; however, you'll have to change the method of application to eradicate indoor pests. Instead of using powder to combat your infestation, mix the DE with water to create a more efficient solution to access the plant's cubbyholes and hard-to-reach areas. Add one tablespoon of DE to 500ml of water (0.11 imperial pints) and mix well. Finely mist both sides of the leaves and its stems so that the plant is covered in a thin film, which will begin its work within twenty-four hours once dry. Its eggs may be immune to the pesticide, so it's important to perform another fine spray seven days later to attack to the recently-hatched larvae. As you have followed the first three steps mentioned in the previous section, you shouldn't see any signs of an infestation for several weeks. We'd recommend waiting six weeks before deeming the specimen pest-free, as relapses of later-hatching larvae could occur. If pests do return, follow the three steps mentioned above, along with the misting of its foliage with this solution. If the infestation is large, you may wish instead to opt for a chemical-based pesticide to destroy the infestation more effectively. DE is considered safe to both pets and humans and has no links to the development of illness or cancers.

Insecticidal or Horticultural Soap is another popular organic pesticides on the market, and there are three versions to consider. The first way is by purchasing an RTU (ready-to-use) spray bottle, which can be immediately used on the plants. Although most garden centres will stock this, it's far more economical to purchase the second option - concentrated bottles. This method comes with pro's and con's but is far cheaper to use if you have multiple infestations. It's self-explanatory and highly beneficial for the outbreak as long as you use the correct levels of dilution - the only downside is its availability in local centres. It's best to buy this option online as there are many different companies to choose from, with some being cheaper than others. The final and most affordable way is by making it yourself;

There are three ingredients in creating your own insecticidal soap - a vegetable, tree or nut-based oil, non-fragrant dishwashing soap and tap water. Most oils are acceptable, with the most successful being vegetable, sunflower, neem and olive oil. Add two parts oil, one part dishwashing soap and eight parts water to create the dilution. Although it's best to fresh bottled water, tap water that has been allowed to sit for 24hrs is also excellent. Spray the dilution wholly around the plant, empathising both the infestations and the potential-hit areas. This method must be performed weekly over a month or two, along with regular pest inspections - as soon as you see a bug, crush it. As mentioned before, each Blackfly can lay up to twenty eggs per day in her lifetime, meaning that you can't risk even leaving one critter to roam around.

Garlic water is the ukhouseplants' recommended organic remedy for treating Blackfly. 

Natural Predators - The last non-organic method is by acquiring adult ladybirds or green lacewings. Although buying insects may be deemed as cruel or inappropriate, it's a natural, and least time-consuming way to remove the pests. Many online stores will sell the insects, all at varying prices and quantities. Once you've obtained the predators, release them in different sections of the plant, favouring the most infested areas first. They'll make their way around your plant, digesting both the eggs and the adults, leaving you with a potentially pest-free plant. Keep the plant in an enclosed transparent box with the insects, to maximise destruction. Unfortunately, this method can take several days to work and could even be unsuccessful, which is why other methods are favoured.

Click here to purchase Neem Oil, an Insecticidal Spray or natural predators like ladybirds or green lacewings. Garlic cloves can be bought at all supermarkets and vegetable stores throughout the year.

Chemical Pesticides

Most chemical pesticides are bought either as an RTU spray or in a concentrated bottle. Of course, it's far more economical to buy the latter as it'll last longer with multiple infestations, but RTU sprayers are still great for small issues. Both of these methods can be purchased at most garden centres, costing from £3 for RTU sprayers, to £7 for the concentrated variety. 

ukhouseplants recommended concentrated pesticide for most indoor pests. Click here to buy.

If you're looking for something with even more strength, try an Isopropyl Rubbing Alcohol, which can be bought from many online stores. This pesticide will work immediately, killing the Blackfly within a few hours of contact. Follow the manufacturer's recommendations and repeat misting/crushing every two weeks until the infestation has elapsed. 

Click here to buy a chemical-based pesticide or an Isopropyl Rubbing Alcohol concentrate.

Ways to Prevent an Attack in the Future

At the local plant shop or garden centre, regulate and inspect any plants that you wish to buy. Check around the hard-hit areas, for instance, the foliage and new growths, before considering the purchase. Most Blackfly infestations come from already-affected plants, so always keep this in mind when increasing your plant-collection!

Keep the windows shut during the spring when Blackfly are most active.

Change the top layer of the soil when bringing any new plant from a shop. Replacing the top layer of the compost will remove any larvae that may have fallen in, or been deposited by a pest. ukhouseplants does this religiously whenever a new plant enters the house!

Regularly check for pests on your own plants. Although this may sound patronising, many gardeners forget to inspect their indoor specimens. As soon as you see a symptom, keep it quarantined and follow the steps above!

For any more questions or queries about Blackfly, be sure to message us via this link or comment in the section below! 

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